The present invention relates to a method and device for regulating a motion variable representing vehicle motion by ascertaining whether the vehicle is located on a road surface inclined at an angle to the direction of travel of the vehicle. The determination of whether the vehicle is located on a road surface inclined at an angle to the direction of travel of the vehicle is performed at least on the basis of variables that are necessary for monitoring sensors used in the vehicle.
Devices and methods for monitoring sensors used in a vehicle are known from the related art in a variety of modifications.
German Published Patent application no. P 196 36 443 describes a method and a device for monitoring sensors in a vehicle, the sensors generating signals which each represent various physical variables. The device contains means with which identically defined comparison variables can be determined for at least two sensors on the basis of at least the signals generated by them. Furthermore, the device contains additional means with which a reference variable is determined as a function of at least the identically defined comparison variables thus determined. On the basis of at least the reference variable thus determined, monitoring is performed in monitoring means for at least one sensor. In addition to the monitoring means, the device also contains additional means with which, for at least one sensor, the signal generated by said sensor is corrected at least as a function of the reference variable.
The device and the method for monitoring sensors in a vehicle also has a steep curve detector. For this purpose, the corrected yaw rate is converted to a transverse acceleration, taking into account the speed of the vehicle. By comparing the converted transverse acceleration and a measured and offset-corrected transverse acceleration, it is possible to determine whether the vehicle is driving through a steep curve.
Methods and devices for determining whether a vehicle is located on a road surface inclined at an angle to the direction of travel of the vehicle are known in a variety of versions from the related art.
German Published Patent application no. P 197 08 508 describes a method and a device with which a transverse acceleration component depending on the inclination of the road surface is determined and/or with which the transverse acceleration of the vehicle is corrected at least as a function of the transverse acceleration component. With this method and device, various queries are first made to determine whether or not a steep curve condition is met. To determine whether the steep curve condition is met, a query, for example, is used to determine on the basis of the change in float angle and yaw rate of the vehicle, whether the vehicle is oversteered. Another query determines whether the driver is attempting to stabilize the vehicle by steering or braking. If the steep curve condition is met, then a vehicle status is found wherein the transverse acceleration component depending on the transverse inclination of the road surface is determined at least as a function of the slip angle on the rear axle of the vehicle. The transverse acceleration component thus determined as a function of the transverse inclination of the road surface is checked for plausibility and used to correct the transverse acceleration or yaw rate of the vehicle.
Methods and devices for regulating a motion variable representing the vehicle motion are known in a variety of modifications from the related art.
A method and a device for regulating the driving dynamics of a vehicle is described for example, in the articlexe2x80x9cFDRxe2x80x94the Bosch method of regulating driving dynamicsxe2x80x9d published in the automotive engineering journal Automobiltechnische Zeitschrift (ATZ), volume 16, number 11, 1994, pages 674-689. At the same time, this publication shows that different special situations such as an inclined road surface are also taken into account in the regulation in the driving dynamics regulator.
An object of the present invention is to improve upon the steep curve detection contained in a device and a method for monitoring sensors in a vehicle.
One advantage of the present invention in comparison with the related art cited above is that with the device and the method according to the present invention for determining whether a vehicle is located on a road surface that is inclined across the direction of travel of the vehicle, signals and variables that are already available from monitoring some of the sensors used in a vehicle are used for this purpose.
The device according to the present invention includes a first apparatus, in particular sensors, for detecting various variables descriptive of the vehicle motion. Furthermore, the device includes a second apparatus with which identically defined comparison variables for at least two of the first means are detected on the basis of at least the different variables which describe the vehicle motion and are detected with the first apparatus. The device advantageously also contains a third apparatus with which plausibility queries are performed at least on the basis of the identically defined comparison variables to ascertain whether the vehicle is located on a road surface inclined across the direction of travel of the vehicle. The result of the determination performed with the third means is taken into account in regulating the motion variable representing the vehicle motion.
It is of particular advantage when the result of the determination performed with the third apparatus is taken into account in determining the identically defined comparison variables and/or if the result of the determination performed with the third apparatus is taken into account in the third apparatus for monitoring at least one of the first apparatus, and/or if the result of the determination performed with the third apparatus is taken into account in a fourth apparatus which generate at least control signals for actuators at least on the basis of the various variables describing the vehicle motion detected with the first apparatus for regulating the motion variable representing the vehicle motion, the control signals being used to influence at least the forward drive and/or breaking torques acting on the wheels of the vehicle.
It is especially advantageous if the identically defined comparison variables determined with the second apparatus represent a physical variable or a variable describing the vehicle motion, preferably corresponding to a variable, in particular a yaw rate, detected with the first apparatus present in the vehicle.
The following plausibility queries are advantageously performed in the third apparatus and/or the following variables are determined for the plausibility queries:
On the basis of the identically defined comparison variables, at least one plausibility query is performed, determining whether the identically defined comparison variables are arranged in accordance with at least one predetermined arrangement as a function of their values. The minimum of one predetermined arrangement describes cornering on a road surface inclined across the direction of travel of the vehicle. On the basis of the identically defined comparison variables, at least one variable is determined which describes the deviation between the identically defined comparison variables. Furthermore, a variable is determined which describes the change in the difference over time, said difference being formed from a variable describing the transverse acceleration acting on the vehicle and a comparison variable for the transverse acceleration. To ascertain whether the vehicle is on a road surface inclined across the direction of travel of the vehicle, at least the result of the minimum of one plausibility query and/or the variable describing the deviation between the identically defined comparison variables and/or the variable describing the change over time in the difference formed from the variable describing the transverse acceleration acting on the vehicle and the comparison variable for the transverse acceleration is taken into account.
The comparison variable for the transverse acceleration is advantageously determined on the basis of a variable describing the vehicle speed and a reference variable formed at least on the basis of the identically defined comparison variables. The reference variable determined here represents a physical variable which preferably corresponds to a variable, in particular a yaw rate, determined with a first apparatus present in the vehicle.
To form the variable which describes the deviation between the identically defined comparison variables, a variable is advantageously determined for each of the identically defined comparison variables, describing the deviation in this identically defined comparison variable from the other identically defined comparison variables. It is especially advantageous if a variable describing the deviation of this identically defined comparison variable from the other identically defined comparison variables of this part of the identically defined comparison variables is determined to form the variable describing the deviation of the identically defined comparison variables from one another for part of the identically defined comparison variables for each of these identically defined comparison variables of this part.
Another advantage is that the variable describing the change over time in the difference formed from the variable describing the transverse acceleration acting on the vehicle and the comparison variable for the transverse acceleration is implemented in the form of a counter. This counter is incremented when the change over the time is greater than a first threshold value. It is decremented when the change over time is smaller than a second threshold value, and it approaches a predetermined value, in particular 0, when the difference over time remains almost unchanged.
Whether the vehicle is located on a road surface inclined across the direction of travel of the vehicle is advantageously determined with the help of a counter. If the counter status is greater than a predetermined threshold value, the vehicle is located on a road surface inclined across the direction of travel of the vehicle. The counter is advantageously incremented at least as a function of the following conditions: The minimum of one predetermined arrangement of the identically defined comparison variables exists and/or the variable describing the deviation between the identically defined comparison variables is greater than a first threshold value, or the absolute variable of the variable describing the change over time in the difference formed from the variable describing the transverse acceleration acting on the vehicle and the comparison variable for the transverse acceleration is greater than a second threshold value. The counter is advantageously decremented at least as a function of the following conditions: None of the predetermined arrangements of the identically defined comparison variables exists and/or the variable describing the deviation between the identically defined comparison variables is smaller than a first threshold value, and the absolute value of the variable describing the change over time in the difference formed from the variable describing the transverse acceleration acting on the vehicle and the comparison variable for the transverse acceleration is less than a second threshold value.
In addition, it has proven advantageous that the determination of whether the vehicle is located on a road surface inclined across the direction of travel of the vehicle is performed only when the variable describing the vehicle speed is greater than a respective threshold value and/or when the absolute value of a first identically defined comparison variable is greater than the absolute value of a second identically defined comparison variable.